A fresh perspective on an extraordinary cluster of galaxies

Galaxy clusters are often described by superlatives. After all, they are huge conglomerations of galaxies, hot gas, and dark matter and represent the largest structures in the Universe held together by gravity.

Galaxy clusters tend to be poor at producing new stars in their centers. They generally have one giant galaxy in their middle that forms stars at a rate significantly slower than most galaxies - including our Milky Way. The central galaxy contains a supermassive black holeroughly a thousand times more massive than the one at the center of our galaxy. Without heating by outbursts from this black hole, the copious amounts of hot gas found in the central galaxy should cool, allowing stars to form at a high clip. It is thought that the central black hole acts as a thermostat, preventing rapid cooling of surrounding hot gas and impeding star formation.

New data provide more details on how the galaxy cluster SPT-CLJ2344-4243, nicknamed the Phoenix Cluster for the constellation in which it is found, challenges this trend. The cluster has shattered multiple records in the past: In 2012, scientists announced that the Phoenix cluster featured the highest rate of cooling hot gas and star formation ever seen in the center of a galaxy cluster, and is the most powerful producer of X-rays of all known clusters. The rate at which hot gas is cooling in the center of the cluster is also the largest ever observed.

New observations of this galaxy cluster at X-ray, ultraviolet, and optical wavelengths by NASA's Chandra X-ray Observatory, the Hubble Space Telescope, and the Clay-Magellan telescope located in Chile, are helping astronomers better understand this remarkable object. Clay-Magellan's optical data reveal narrow filaments from the center of the cluster where stars are forming. These massive cosmic threads of gas and dust, most of which had never been detected before, extend for 160,000 to 330,000 lights years. This is longer than the entire breadth of the Milky Way galaxy, making them the most extensive filaments ever seen in a galaxy cluster.

These filaments surround large cavities - regions with greatly reduced X-ray emission - in the hot gas. The X-ray cavities can be seen in this composite image that shows the Chandra X-ray data in blue and optical data from the Hubble Space Telescope (red, green, and blue). For the location of these "inner cavities", mouse over the image. Astronomers think that the X-ray cavities were carved out of the surrounding gas by powerful jets of high-energy particles emanating from near a supermassive black hole in the central galaxy of the cluster. As matter swirls toward a black hole, an enormous amount of gravitational energy is released. Combined radio and X-ray observations of supermassive black holes in other galaxy clusters have shown that a significant fraction of this energy is released as jets of outbursts that can last millions of years. The observed size of the X-ray cavities indicates that the outburst that produced the cavities in SPT- CLJ2344-4243 was one of the most energetic such events ever recorded.

However, the central black hole in the Phoenix cluster is suffering from somewhat of an identity crisis, sharing properties with both "quasars", very bright objects powered by material falling onto a supermassive black hole, and "radio galaxies" containing jets of energetic particles that glow in radio waves, and are also powered by giant black holes. Half of the energy output from this black hole comes via jets mechanically pushing on the surrounding gas (radio-mode), and the other half from optical, UV and X-radiation originating in an accretion disk (quasar-mode). Astronomers suggest that the black hole may be in the process of flipping between these two states.

X-ray cavities located farther away from the center of the cluster, labeled as "outer cavities", provide evidence for strong outbursts from the central black hole about a hundred million years ago (neglecting the light travel time to the cluster). This implies that the black hole may have been in a radio mode, with outbursts, about a hundred million years ago, then changed into a quasar mode, and then changed back into a radio mode.

It is thought that rapid cooling may have occurred in between these outbursts, triggering star formation in clumps and filaments throughout the central galaxy at a rate of about 610 solar masses per year. By comparison, only a couple new stars form every year in our Milky Way galaxy. The extreme properties of the Phoenix cluster system are providing new insights into various astrophysical problems, including the formation of stars, the growth of galaxies and black holes, and the co-evolution of black holes and their environment.

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User comments

The only "fresh perspective" of the galaxies, galaxy-clusters and the universe in general one can have is to reject the perspective of official cosmology based on the the fairy tales of GR, Big Bang, dark/black cosmic monsters and so on. Continuing on this perspective will only bring more surprises, wonder, bafflement, mysteries with continuing new findings, because this whole official "perspective" is based on magic and mysteries of mathematics!

An exactly opposite "perspective" based on (anti-causality) dialectical chance and necessity; quantum electrodynamics and uncertainty principle can explain the findings (so far) of modern astrophysics and prevent future bafflements.Gravity is an electro dynamical property of matter involving graviton orbitals (like molecular orbitals in chemistry) that explains the (quantized) shell and ring like structures of the galaxies and the clusters. http://www.amazon...0414445.

The question I keep wondering is whether astrophysicists have asked: "what function is being facilitated by the filaments"? It's a pretty well-accepted fact of design that form facilitates function, and that fact is present in pretty much any natural, dynamically evolving system. One of Darwin's central arguments in favor of evolution involve his finches, and the different beaks each one developed to best capture/eat the local food sources available on each isolated island. Everything acts and evolves to perform the work it needs to most efficient way possible. So what possible function could meet the form of unbelievably massive plasma filaments other than current flow? Why should filaments be ubiquitous features of the entire universe - from our solar system, to our galaxy, to galaxy filaments - if they're not all performing the same function? Why should these structures even be plasmatic if not for current flow?

If a species of bird develops a critically unique form for itself over just a few hundred, maybe thousands years of isolation on one island, than I think it's ridiculous to assume that these clusters, or even our own galaxy - which Herschel demonstrated this July is ubiquitous filamentary - should spend millions of years evolving into a filamentary form if that form shouldn't be serving some purpose. Hell, even water carves the riverbed out naturally as it flows into these serpentine structures so as to best maintain a cooler, average temperature. Why should galaxies or galaxy clusters carve themselves out into these filaments, if not to create a form that is best suited to some purpose? The only sensible function that stands out to me is current flow.

Correction: Instead of "Gravity is an electro dynamical property of matter involving graviton orbitals" it should be "Gravity is a quantum electro-dynamics (QED) based property of matter involving graviton orbitals".

The rate at which hot gas is cooling in the center of the cluster is also the largest ever observed.

This cooling function is simply an assumption of a committed merger maniac. The maniac cannot conceive how else so much activity in the center could occur with the condensation of gas into stars. So he assumes inflows of cool gas, rather than outflows of newly formed gas from the central core.

How is possible the formation of large cosmic structures, since according to the apologists of the big bang, expansion of the universe dominate gravity? Why many modern scientist are looking for dark matter after the cosmic vacuum is real physical structure with certain properties that determine the behavior of elementary particles in various sectors of space? Because the wages?

"the black hole may be in the process of flipping between these two states."The idea of two states seems not generally accepted. E.g.:"Today most astronomers believe that quasars, radio galaxies and the centres of so-called active galaxies just are different views of more or less the same phenomenon: a black hole with energetic jets beaming out from two sides. When the beam is directed towards us we see the bright lighthouse of a quasar. When the orientation of the system is different we observe it as an active galaxy or a radio galaxy. This 'unified model' has gained considerable support through a number of Hubble observational programs. ..."http://www.spacet...k_holes/A nice presentation on this:http://www.astro....re12.pdf

"the black hole may be in the process of flipping between these two states."

Let me add another 2 cents for LaViolette. This active/inactive state is central to his model, where he suggests perhaps 15 percent of massive galaxies have cores in the active state. While he remains unpopular, eventually his model will will out.

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